Low HR Training

Increasing my long run/MAF training (Read 360 times)

I did some MAF training over the summer and then did some faster training preparing for a race in the autumn. I am hoping to run my first marathon in May and have been basebuilding use low HR the past 3.5 weeks.
I am using the Team Oregon basebuilding schedule for beginners, and am gradually increasing my long runs and weekly mileage and I am running more miles now than I have ever have before (see below)
2 weeks ago: 12 mile long run/30 total miles
last week: 13.1 mile long run/31.5 total miles
I am noticing something interesting on my long runs the past 2 weeks. I can bascially keep pace for most of my run, and then my pace drops off dramatically the last 2 miles in order to stay under MAF. For example, December 8th I ran a pretty steady 11:30-ish pace for 10 miles with a HR in the low 140s. My 11th mile was a 12:30 and my 12th mile was a 13:30. I had similar results yesterday, except I was able to maintain pace for 11 miles and then I dropped off in my 12th and 13th miles.
My questions:
1. Any idea what is happening to make my pace fall apart in the last miles. Is my aerobic system basically failing from fatigue?
2. Does my pace falling off in the late miles mean that I am not ready for that mileage? In other words, I ran 13 miles yesterday but maybe I should have only ran 11.
3. Is my pace falling off the last few miles exactly what is supposed to happen during basebuiding? For example, next week I may run 14 miles and keep pace through 12, then the next week run 15 and keep pace through 13. If I keep seeing this progress- should I stay with the Team Oregon schedule?

That's not uncommon in the beginning, as your slow-twitchers aren't developed enough yet and are petering out. Lack of hydration can add to it as well. Also, lack of a good warm-up. You can also map out your "heart rate performance plan" in way that keeps you a bit more even. Here's an example of a recent long run. The faster start and slower end is due more to the extreme tail and face winds I experienced :
19 miles 11:38 pace
42 oz of water drank
no nutrition
no breakfast/empty stomach thoughout run
13:03 99 bike trail winds 16 -30mph gusts sunny
I tr11:12 111 (tail wind and down river for 5.5 miles)
11:12 114
11:23 116
11:22 118
11:39 119 (Head wind and upriver for 5.5 miles)
11:47 120
11:40 122
11:49 124
11:52 126 (hill)
11:51 126 (long incline)
11:19 126 (tail wind and down river for 4 miles)
11:24 129
11:26 129
11:23 129
11:59 133 (head wind and upriver for 4 miles)
11:49 134
11:57 134 (hill)
12:05 134 (long incline)
HR plan:
miles 1-6: ave 100-119
miles 7-12: 120-126
miles 13-19 127-134
I try to get to 119 by mile 5, the hold that pace for the rest of the run. It gives me an even feel. Of course winds and hills will cause slowing or speeding to either side of the average. Essentially, the last three miles were run at the same pace and HR. I like to do this on long runs to practice the feel of even pacing I find that it usually gives me the room I need by the end.
Maybe this will help.
Keep going!
--Jimmy

Yeah, this is like the second phase of development. The first phase is a simple improvement of
pace at a given heart rate for the first couple of miles of a run. The second phase is that of
maintaining that pace over longer and longer distances with reduced heart rate drift. It takes
time just like the first phase and it can only really be addressed by acclimating to those longer
distances. Extend your long run distance and you will certainly see it in those last few miles.